My cats on my MCX 350 2008 X15 are over heating. Does anyone have any idea why this would happen? The temp gauage bounces all over the place between 120 and 220. Seems like water is being restricted to the cats. Any ideas what I should look at? New impleller, plenty of water getting circulating.

Huskie05

06-06-2011, 03:58 PM

My cats on my MCX 350 2008 X15 are over heating. Does anyone have any idea why this would happen? The temp gauage bounces all over the place between 120 and 220. Seems like water is being restricted to the cats. Any ideas what I should look at? New impleller, plenty of water getting circulating.

Thermo going bad? not reading right is my guess.

scott023

06-06-2011, 04:03 PM

I'd check your thermostat right off the hop.

vision

06-06-2011, 04:22 PM

The CATS are hot or your engine temp? The catalytic convertor is usually at a temp much higher than 220F. But if your engine in general is overheating, then impeller, raw water strainer at the bottom of the transmission cooler tube, and T-stat would be were I would start. The T-stat on my 2008 MCX went bad last year leading to over heating.

Iskidaily

06-06-2011, 05:17 PM

How hard is it to replace a thermostat and how do you check it? Just replaced my impeller and still getting overheating after the boat sits with engine off between runs

edge0

06-06-2011, 06:23 PM

well seems like my CATS are fired! What's engine warranty...2 years?

Spork

06-06-2011, 06:41 PM

Dont know about boat warranty but there is federal emission warranty on catalytic converters of 8yrs or 80, 000 miles for your vehicles...

vision

06-06-2011, 07:19 PM

well seems like my CATS are fired! What's engine warranty...2 years?

3 years. I would certainly contact you MC dealer and if they are no help Indmar as your CATX should last a long time.

edge0

06-06-2011, 10:40 PM

3 years. I would certainly contact you MC dealer and if they are no help Indmar as your CATX should last a long time.

someone told me that they reccomend that new inserts be installed every 300 hours.....sounds fishy to me and I never saw this in any manual or bulletin.

out of curiosity. say one was to remove the cat inserts. what would that do? there is only an O2 sensor before the cat (not even sure what this is reading) so doesn't seem like anything would run different??

Spork

06-06-2011, 11:38 PM

someone told me that they reccomend that new inserts be installed every 300 hours.....sounds fishy to me and I never saw this in any manual or bulletin.

out of curiosity. say one was to remove the cat inserts. what would that do? there is only an O2 sensor before the cat (not even sure what this is reading) so doesn't seem like anything would run different??

If its open after the o2 sensors anyway there will be no harm to the engine just pollution and that will make al gore and california very upset, I'd remove them and maybe pickup a few extra hp and not worry about it...

Spork

06-06-2011, 11:45 PM

On to the problem of why the catx went out and is hot, usually cats fail is either from misfires or running lean causing the cats to overheat and either melt or simply break apart. I don't think a cooling issues will cause this however if the cats are stopped up they might prevent water from escaping the manifolds properly causing the engine to possible over heat, your might have 2 problems here...

edge0

06-07-2011, 12:08 AM

bad fuel pump could cause a lean condition.

what about FAE. If someone had that on their boat could that cause enough restriction to cause a lean condition?

anyone here with a MCX with CATX that heard about this 300 hour replacement?

good thing is I still have 130+ in every cylinder

Spork

06-07-2011, 12:17 AM

bad fuel pump could cause a lean condition.

what about FAE. If someone had that on their boat could that cause enough restriction to cause a lean condition?

anyone here with a MCX with CATX that heard about this 300 hour replacement?

good thing is I still have 130+ in every cylinder

Yes a bad or weak fuel pump or a restricted fuel filter can cause lean conditions most likely the pump needs replacing, I don't think a FAE is your problem because thats at the end of the exhaust system...

vision

06-25-2011, 11:09 PM

So here is my stupid question. How do you know your catalytic convertors are over heating besides the rubber exhaust hoses begin to melt?

My 08 MCX is going to limp mode because of a Catalytic Converter A temp sensor high voltage reading. I am going to replace both sensors in case there is a short.

But if the cats are truly hot, how do you tell (besides my new sensors giving the same error)? They do not seem hotter than normal when you open the engine hatch. Engine temp and performance are normal.

Spork

06-25-2011, 11:54 PM

You could use a infared thermometer and check both sides front and rear of cats and compare temperature a normal cat will have a temperature difference before cats and after cats, if the temperature is the same then it has failed. you cant compare the temp feel of a boat to a car, boats will be drastically less...

vision

06-26-2011, 12:58 AM

You could use a infared thermometer and check both sides front and rear of cats and compare temperature a normal cat will have a temperature difference before cats and after cats, if the temperature is the same then it has failed. you cant compare the temp feel of a boat to a car, boats will be drastically less...

Thanks. I knew there must some way to check functionality.

Thrall

06-26-2011, 03:05 PM

To the OP, how do you know they are bad? (glad I bought a 06, btw. Even though they should be reliable, just another thing to break or maintain)
And FWIW, your temp will be up considerably after the a run with the engine off. Everything heat soaks with no water running thru it, but should cool back to 160 quickly after restarting.